The future of letter grades for public schools is unclear less than five years after the Louisiana Legislature ordered them to begin.

The annual marks, which have sparked bitter arguments, were already partly on hold for the past two years, and Louisiana’s top school board will be asked next week to extend that another year.

Two of four contenders for governor — Democrat John Bel Edwards and Republican Scott Angelle — said last week that the grade law was a mistake or should be shelved for an overhaul.

Even the leader of the third-rated school district in the state, which carries an A rating, questioned whether the grades make sense, especially amid repeated revisions in how they are calculated.

“When is it going to be stabilized so you know where you stand?” asked Michael Faulk, superintendent of the Central School District.

The sentiments represent a major change since 2010, when the grade requirements breezed through the state House and Senate at the urging of Gov. Bobby Jindal.

The argument then was simple: rate schools with a system that parents and others can understand.

Under the previous ratings, schools were assigned stars linked to annual school performance scores, which triggered complaints that no one understood what the stars meant.

“You need to have a letter grade to tell you what is going on in that school,” said Barry Erwin, president of the Council for a Better Louisiana.

The initial report in 2011 showed that 44 percent of public schools were rated D and F, which set off something of a political firestorm. It also helped pave the way for Jindal’s education overhaul in 2012.

But the state Board of Elementary and Secondary Education voted in early 2014 to revamp the grading system during the move to Common Core, which includes new classroom standards in reading, writing and math.

Under what was supposed to be a two-year plan, the overall distribution of grades for the 2013-14 and 2014-15 school years would not differ from the 2012-13 results.

Schools whose state performance scores stayed the same or rose would not drop a letter grade.

BESE took the action amid fears that, without safeguards, the tougher standards would cause letter grades to plummet.

Last year, 28 percent of schools were rated D and F, the same as the previous year.

State Superintendent of Education John White said last week that, in line with the recommendations of a special panel, he will ask BESE to extend the curve policy for a third school year — 2015-16.

Senate Education Committee Chairman Conrad Appel, R-Metairie, who handled the grades bill on the Senate floor in 2010, said he is OK with the extension — for now. “I have no problems at all with extending that time frame and allowing more time for the kids to become acclimated to higher expectations,” Appel said.

However, he said the curve policy should not be open-ended. “There is a point in time when we have to have a clean break and say, ‘This is what an A means; this is what a C means,’ ” he said.

Erwin, whose group backs the grade requirements, said he too has no objections to extending the curve policy another year. It may be a problem to return the grades to their earlier version amid fierce opposition from teachers unions and school boards, he said.

“We are going to have some fights on our hands to get it back to a purer state,” Erwin said, a reference to the original grading system. “They hate it.”

Letter grades opponents contend the marks are misleading and fail to capture the whole picture of a school’s quality.

Steve Monaghan, president of the Louisiana Federation of Teachers, called the letter grades a “political device” adopted in Louisiana in response to a national push by then-Florida Gov. Jeb Bush.

“It hasn’t produced,” Monaghan said of the bill’s initial promises.

In the first three years the state issued the grades, the state had 44 percent, 36 percent and 28 percent of schools rated D and F.

However, changes in how the grades are calculated, including the addition of bonus points, affected the results even before state education leaders ordered the distribution to remain the same 13 months ago.

Faulk said school climate, safety and the makeup of the staff should be calculated, too.

“There are more factors than just relying on assessments,” he said.

During a two-hour gubernatorial forum in Shreveport on Tuesday, Angelle said the grades can be useful but need another look.

“We need to freeze any letter grades until we get that methodology right,” the Breaux Bridge resident said.

Edwards, a state lawmaker from Amite, voted against the 2010 law. He said he had been concerned the grades would present a false picture. “That is exactly what happened,” he said.

Follow Will Sentell on Twitter, @WillSentell. For more coverage of Louisiana government and politics, follow our Politics blog at http://blogs.theadvocate.com/politicsblog.